var = 'Hi'
def fun1():
    #global var#即使屏蔽这句 结果也是一样的
    var = ' Bady '
    return fun2(var)
def fun2(var):
    var += 'I love you'
    fun3(var)
    return var
def fun3(var):
    var = 'I love you too'
print(fun1())
